Weird Issue While Trying to Initialize a 2-D Matrix (Python)

Question

While I initialize a square matrix with all elements as 0 and try to manipulate one of the elements, a weird "bug" happens:

Here is the sample code for a 3 * 3 matrix:

row = [0] * 3
matrix = []
for i in range(3):
    matrix.append(row)

matrix[0][1]=2

I try to change one element say matrix[0][1] to 2, all elements on the column 1 change to 2

[0,2,0]
[0,2,0]
[0,2,0]

Can anyone please help explain what's going on here? I only try to change one element only.